Abstract:MRS, M17, and three other culture media were used to isolate lactic acid bacteria (LAB) from 12 samples of naturally fermented dairy products collected from the herdsman families in the northern areas (Yili, Bole, and Tacheng) of Xinjiang, and the physiological and biochemical phenotypes were characterized. The LAB isolates were analyzed by 16S rRNA sequencing to construct phylogenetic trees and initially establish their evolutionary position at the genus level. Subsequently, the identification and classification of LAB at the genus level were conducted using species-specific primers for LAB. One hundred and sixty strains of suspected LAB were isolated from the samples, and most strains showed a broad temperature-adaptability. The majority of strains belonged to the genus Bacillus. Based on the phylogenetic tree, the LAB isolated from traditional dairy products belonged to seven genera: Lactobacillus (78 strains), Carnobacterium (three strains), Weissella (one strain), Lactococcus (22 strains), Enterococcus (47 strains), Streptococcus (eight strains), and Vagococcus (five strains). Species-specific polymerase chain reaction (PCR) identification showed that Lactobacillus isolates mainly belonged to four species. By the Oxford cup method, ten Lactobacillus strains were screened, and they showed inhibitory effects on gram-negative Escherichia coli and gram-positive strains such as Bacillus subtilis, Listeria monocytogenes, and Staphylococcus aureus. This study lays a foundation for the application of LAB as biopreservatives in the food industry.
